USB DAC Recommendation

The Ayre QB9 is plug and play with extremely little setup. Ayre also provides detailed setup for Mac based systems on their website. The current unit is 24/192 and with your setup should adjust on the fly depending on the source content specs. Plus Ayre is pretty good about adding any upgrades for cost of parts/software in case HiRez bumps up to 384 standard (unlikely in near future). There happens to be a virtually brand new one for sale right now.

Full disclosure: The one I mention for sale is mine.

The problem with the W4S are the proprietary drivers needed to run on the source machine vs. the native OS drivers used by Ayre/Wavelength.

Changes in operating system framework may require these drivers to be updated which could become problematic.

@Face: Nobody said there was an issue with the existing drivers and to be clear it's an issue with all USB DACs right now for anything above 24/96 on Windows and Mac OS X < 10.6. Only Snow Leopard has native USB Audio Class 2 drivers which allows 24/192 without additional software. So Ayre/Wavelength/etc all fall into this category not just W4S, sorry for sounding like I was singling them out.

@Marakanetz: This assumes you keep the same music server forever and never ever want to upgrade which is a rarity in this hobby. We all strive the latest/greatest/best so if an upgrade gives additional capability at the expense of broken drivers you'll find your self in a pickle. Is this scenario super likely...probably not.

@Goatwuss: And a lot of older PC hardware (especially those you mention) have legacy issues on newer OS builds so you've only confirmed my comment but yes as you point out as long as the company is around and the challenge is not insurmountable (or expensive) it's likely an update will be possible.